The importance of temperature control is well established for interior enclosures in which livestock, including poultry such as chickens, are housed, i.e. livestock enclosures or environments. Excessive or insufficient enclosure temperature can result in animals with physiological stress, which can cause illness. For example, chickens may often become ill if the enclosure temperature of the enclosure in which they are housed declines below 79 degrees Fahrenheit (79° F.) or may begin to suffocate if the enclosure temperature rises above 89° F. Further, such conditions may also detrimentally affect animal growth and, for chickens, production of eggs. Obviously, slower rates of growth and such lowered production increase the costs to the producer thus lowering profit.
To address this concern, modern livestock enclosures generally include some sort of air cooling mechanism to regulate enclosure temperature of the livestock enclosures, during periods of the year when cooling is required, to a target enclosure temperature range within which the enclosure temperature of the enclosure may safely vary for safely housing livestock. For example, for chickens, the target enclosure temperature range is generally, as suggested above, between 79° F. and 89° F. However, cooling livestock enclosures poses particular challenges in that such enclosures must typically be well-ventilated with high levels of air circulation from the outside to ensure that noxious gases arising from the presence of livestock excrement and litter can be dissipated. These ventilation requirements typically make use of blown-air air conditioners impractical, since the large volume of air that must be constantly circulated, and cooled, would require excessive amounts of cooling, and, accordingly make use of such systems highly expensive.
One solution used to address these cooling problems for livestock enclosures is the use of evaporative cooling systems and methods. This is particularly the case in the poultry/chicken industry. In evaporative cooling systems, water is pumped by a water pumping system into the livestock enclosures where the water is converted by a misting nozzle into a fine mist, i.e. a fog, of water droplets and distributed thereby or with the aid of ventilation fans into the livestock enclosures. The air in the livestock enclosures absorbs the mist and gives up energy to the water molecules of the water droplets in the mist. This absorption process converts the water droplets into vapor and reduces the temperature of the air in the livestock enclosure, and thereby of the livestock enclosures itself. Such evaporative systems do not require constant blowing of air-conditioned air into the livestock enclosures and thus are often more economical than blown-air cooling systems.
U.S. Pat. No. 4,773,471, issued to Grant et al. on Sep. 27, 1988, teaches such an evaporative cooling system. The system includes a water pumping system having a pump for pumping water to a misting arrangement, namely misting nozzles, for converting the water to the mist and a fan for blowing the mist into the building. However, while the evaporation of the water droplets does cool the livestock enclosures, the amount of cooling possible is limited by water temperature of the water received at the misting nozzles. Specifically, if water provided by the pump to the misting nozzles is not sufficiently cool, there may insufficient cooling of the livestock enclosures by evaporation of water droplets to cool the livestock enclosure to a target enclosure temperature within the target enclosure temperature range, such as, for chickens, a target enclosure temperature between 79° F. and 89° F. Accordingly, the temperature of the water received by the misting nozzles from the pump is of primary importance. In general, evaporative cooling systems having pumping systems which provide pumped high-pressure water to misting nozzles at a room temperature of 65° F. can only cool a livestock enclosure to a temperature of 89° F. Obviously, as 89° F. is at the extreme high end of the target enclosure temperature range for chickens, water pumped to misting nozzles must be received thereby at a water temperature below 65° F. if an evaporative system is to be useful for certain types of livestock, such as chickens. Specifically, to ensure sufficient cooling during hot days, water temperature of the water received at the misting nozzle water must generally be at a target water temperature below 40° F. to sufficiently lower the enclosure temperature to a target enclosure temperature within an enclosure temperature range of 79° F. to 89° F. Accordingly, an evaporative cooling system such as that taught by U.S. Pat. No. 4,773,471 may be insufficient for cooling a livestock enclosure during hot days of the year or in very warm climates.
U.S. Pat. No. 6,367,278, issued to Strussion et al. on Apr. 9, 2002, discloses an evaporative cooling system having a refrigerated water pumping system which includes a pump for pumping the water to high pressure and a water cooler, such as a heat exchanger, which refrigerates the water prior to pumping to the nozzles. Thus, the water may be refrigerated to an appropriate target water temperature prior to pumping to increase the amount of heat absorbed by water droplets from the livestock enclosure during evaporation and thus increasing cooling of the enclosure. However, while a water cooler in an evaporative cooling system as described in U.S. Pat. No. 6,367,278 could be adapted to reduce the water temperature of water prior to pumping to below 40° F., generally required for chickens and some other types of livestock, this would not prevent the water from absorbing heat during pumping by pump to mist nozzle. Accordingly, pumped water may still arrive, despite cooling before pumping, at mist nozzle having a water temperature in excess of the target water temperature, generally below 40° F. when livestock is chicken, required for cooling the livestock enclosures. It may be possible to cool water to an even lower water temperature than the target water temperature for water at misting nozzles to compensate for heat absorption by water during pumping. However, for certain livestock, such as chickens, where the target water temperature, i.e. below 40° F. for chickens, is close to the freezing point of water of 32° F., additional cooling of water below the target temperature prior to pumping incurs a risk that water may freeze, possibly damaging the pump or other components of the refrigerated water pumping system and the evaporative cooling system.
In addition, the amount of heat absorbed by water during pumping may vary based on environmental conditions in the enclosure such as air pressure and outside temperature, as well as the amount of water pressure required by misting nozzles to convert water into mist and the amount of mist required to cool the livestock enclosure.
Accordingly, there is a need for an improved refrigerated water pumping system capable of furnishing pumped high-pressure refrigerated water at a target water temperature to misting nozzles situated in a livestock enclosure for distributing the high-pressure refrigerated water as a mist for evaporation in the livestock enclosure to provide cooling thereof.